Question: I have an apple tree that has developed several twigs with brown, dead-looking leaves and flowers. I don’t see any insects and the rest of the tree looks fine. Do you know what the problem might be?

Answer: I suspect that you are seeing the evidence of fireblight — a bacterial infection caused by the pathogen Erwinia amylovora.

Apple and pear trees are quite susceptible to it, as are ornamentals such as pyracantha. Bees carry the bacteria from flowers of infected twigs to other flowers, spreading the infection during the flowering period.

Unless these infected twigs and branches are removed, the pathogen can overwinter in the cankers formed as a result of infection. Other insects can also spread the infection throughout the year.

Dormant sprays and garden sanitation are only partially effective in controlling the spread of infection. There are other chemical methods of control that are only slightly more effective.The best tactic involves removal of infected tissue. If only a few branches are affected, I would recommend that home gardeners sterilize their clippers with a 10 percent bleach solution (9 parts water to 1 part household bleach) and remove the infected branch.

The clippers should be sterilized before each individual cut is made to prevent possible reinfection from bacteria on the clippers, and again after all cuts are completed. Dispose of all prunings in the trash; do not compost them. The bleach solution corrodes metal tools, so be sure to clean and oil them before putting them away.

Question: Last year I grew carrots for the first time, but many of them were forked. How can I avoid it happening again this year?

Answer: Even professional growers produce some forked carrots. However, if a high percentage of your crop was forked, there was a problem.

Heavy soil or rocks in the soil could be a likely cause.

Some determined gardeners sift a small area of their gardens to a depth of 1 foot to remove possibly damaging rocks. The addition of an organic soil amendment will lighten a heavy soil. If you use manure, be sure it is well‑rotted, because the use of insufficiently rotted manure can also cause forked carrots.

Ottillia “Toots” Bier has been a UC Cooperative Extension master gardener since 1980.